Minor correction of the discussion of angles.

README.md

@@ -58,7 +58,7 @@ Note that the angular sensors used in this setup are incremental encoders. This
 
 ### Incorrectly stated positive direction of travel angle in the documentation
 
-Note that the documentation states the positive direction of the travel angle inconsistently with the measurements. The documentation says that the travel angle `λ` increases for counterclockwise motion, but is not only in disagreement with the measurements but also does not comply with the conventions in aerospace. The travel angle `ψ` in this experiment corresponds with the yaw angle as used in the aerospace (angle around the vertical body axis), for which [the common conventions is that it is positive when turning to the right](https://en.wikipedia.org/wiki/Flight_dynamics_(fixed-wing_aircraft)).    
+Note that the documentation states the positive direction of the travel angle inconsistently with the measurements. The documentation says that the travel angle `λ` increases for counterclockwise motion, but this is not only in disagreement with the measurements but also does not comply with the conventions in aerospace. The travel angle in this experiment corresponds with the yaw angle `ψ` as used in the aerospace (the angle around the vertical body axis), for which [the common conventions is that it is positive when turning to the right](https://en.wikipedia.org/wiki/Flight_dynamics_(fixed-wing_aircraft)).    
 
 ![Roll, pitch, yaw](figures/1280px-Yaw_Axis_Corrected.png)